Automatic mixing and discharging system for plural liquids



Apr-i127, 1926. 1,582,278

I. W. KNIGHT AUTOMAFIC MIXING AND DISGHARGING SYSTEM FOR PLURAL LIQUIDS Filed July 28- 1924 INVENTOR ATTORNEYS Patented Apr. 27, 1926.

UNITED STATES PATENT OFFICE.

IRA w. KNIGHT, or onnnsron, RHQDE ISLAND, essrenon To GENERAL FIRE EX- TINGUISHER COMPANY, or rnovrnnncn, RHODE ISLAND, A CORPORATION or DELAWARE. I

AUTOMATIC MIXING AND mscnnnerne sYs'rEiu non PLURAL mourns;

Application filed July 28, 1824;. SerialNo. 723,579.

To all whom it may concern:

I Be it known that I, IRA TV. KNIGHT, a citizen of the United States, residing at Cranston, in the county of Providence and State of Rhode Island, have invented certain new and useful Improvementsin Automatic Mixing and Discharging Systems for Plural Liquids, of which the followingis, a specilication.

This invention relates to improvements in automatic'mixing and. discharging systems for plural liquids. More particularly it relates to iire extinguishers systems in which two liquids are provided, and kept separate until thesystem is to operate, and which are then to be discharged together, these liquids being such that by a chemical reaction which occurs between them a fire extinguishing product results. A number of liquids which can be thus combined are well known, one of them being ordinary acid, as sulfuric acid, or, n'eferably for many purposes, a solution of aluminum sulfate, and the other being alkali, as a solution ofbicarbonatehf soda; and the fire extinguishing product may be either merely carbon dioxide gas; or may be a foam in which thiso' any gas is held in tough bubbles forming a blanket adapted to cover the surface which is to be protected.-

The material for forming the foam maybe introduced by methods already well known. Whether there beiwo or more liquids .to be put together, it is desirable to keep separate from each other the two which react, as the acid and the alkali, and to have them auto matically putctogether when needed. The valve for discharging them may be automatic as int-he case of the ordinary fire. extins guishing sprinkler, or maybe operated by hand, but in either case the apparatus to which the invention applies is one in which the liquids stand readyto flow, and auton'iatieally to come together for the reaction to occur upon the opening of the VZ- 'lY,

which herein .is assuined'to be anordinary sprinkler thermally responsive so that it opens upon the occurence, of a. predetermined rise in temperature.

It has already been proposedthat the desiredifiow of: the two liquids-1 might be ar ranged if there were siphons leading them to the. sprinkler, preferably under equal head. -Th1s ordinarily involves a preliminary pr ming of the s1phons,requ' "ing the opening of a vent at the top of the siphon during thefilling operation, followed by closure 'ofthe. vent. 1n apparatus intended for lire protective purposes it-is very important that the risk of human oversight should be made assmall as possible, and to this end is is a purpose of the present invention to eliminate, the danger of such a vent being left open, in apparatus having a siphon, by devisinganeans to do away with the vent entirely. :This is accomplished, according to the invention, by arranging for the force of gravity actingon one of the liquidsto operate through that liquid on the principle of the ejector to draw the other liquid up over the crest of its siphon and thus to set the siphon into action coincidentally with the outflow of the first n entioned liquid which begins assoon the sprinkler is opened.

One embodiment of this invention isillustrated in the accompanying drawing, to-

gether with a modified form which may be used in some cases; and it will be obvious that various other.modifications may be'dcvised to suit special circumstances or preferences. It isintended that the patent shall cover by suitableexpression in the appended claims, whatever features of patentable novelty exist in the invention disclosed lnfthe accompanying drawings:

. Figure 1 is side elevation partly insection through a tank containing the two liquids, which are to be kept apart until their operation is needed and then to be united automatically upon the opening of a sprinkler; showing also a minimum sprinkler system of piping, having a single outlet imn'iediately below the containers; and

Figure 2 is a similar elevation of a modilied form of a detail.

Referring to the drawings, the tank 10 is separated by partition 12 so as toconstitute a pair of containers, let and 1 6, one of which (14) is assumed to hold the acid liquid, otherwise known commercially as the A solution, and the other of which (1(3) holds the alkali or B solution. Many liquids are known which may be used for A but they are generally or always corrosive by nature, so that this container-H has a tank lining 18 of lead or other resistant material, and the siphon pipe 20 which stands within is also of lead. The other liquid being non-corrosive, it is preferred to place the operating parts of the mechanism in it. These consist of the discharge end of the siphon 20, which rises out of the corrosive liquid A and descends into and through the non-corrosive liquid B, and comes .to an end near the bottom of the container 16 where it constitutes the internal member of an ejector 22 whose external wall surrounds the end of the siphon 20, is open to receive liquid B from the container 16 and is arranged to convey that liquid downward as an envelope around the liquid issued from the end or" the siphon 20, and to carry the two together through the bottom of the container 16 and the distribution piping 2a to the place of discharge which is represented by the sprinkler 26. Although this is shown close under the containers and the latter are relatively small, it will be understood that the containers may be of any size, that the piping system from them may lead to any distance and with any desired branches, and that the sprinklers may be of any desired number and type and may be either automatic or under hand valve control; and may be arranged to sprinkle or merely to discharge the material which issues through them.

In the system thus described the corrosive liquid A rests quietly in its container having no access to the other liquid until it is needed to be operative, and is held thus by gravity. The non-corrosive liquid B likewise rests quietly in its container being held by the closed valve 26. Whenever this valve opens the flow of liquid B begins and this, on the principle of the ejector, draws contents of the discharge leg 20 of the siphon tube 20 downward with it, producing a suction all along that tube. The lower part of said contents will be liquid like that in container B. Next above it will be a slug of air. The suction immediately starts all contents of the discharge leg of the siphon moving downward, and this pulls the contents of the intake leg upward with suflicient force to move them over the crest and thus set the siphon into action. Thereafter the two liquids together flow through the single pipe 24; of the system to the discharge 26 and perform their normal function. The making of the mixture in proper proportions can be controlled by proper design of the size of the orifices. In this connection it will be observed that by the invention it is possible to use the acid in its desirably diluted form having a specific gravity closely approaching that of the alkali liquid and having a volume closely approaching the volume of the latter. It has been shown, by the operation of apparatus constructed to embody the invention, that when thus arranged the two liquids flow with such average uniformity that their supply becomes exhausted sub stantially simultaneously. The initial outflow will be solely of liquid B, followed by a brief period of B mixed with air, and then the standard mixture of B with A. The suction from the relatively high velocity and momentum of the B liquid due to the greater initial head propelling it may be expected to augmentthe rate of flow of the acid beyond that which would be due solely to its own head or difference between the levels of its two ends; and after that the gradual decrease of head of the B liquid and the maintenance unchanged of the operative head of the A liquid may be expected to maintain an approximately proportional mixture.

To charge the apparatus, the valve 26 being closed, it is only necessary to pour the liquids A. and B into their respective containers. lVhichever enters first rises freely within the leg of the siphon which is within its container 14 or 16; and whichever enters later rises part way in the other leg, compressing ahead of it air, which is trapped therein, so that in the end each liquid rises partway in the siphon, and these two parts are kept well separated and at approximately equal elevations below the top by the body of air which is trapped in the top of the siphon.

In Figure 1 the wall 22 of the ejector is shown closed about the leg 20; and the entrance for the B liquid is provided hrough an elbow 28 and nipple 30. This arrangement prevents deposit of any falling sediment from lodging in the ejector or discharge pipe 24. A more simple arrangement is shown in Figure 2 where the ejector 22 has an open top and the leg 20 01" the siphon extends downward through this opening a suitable distance into the envelope of B liquid within the ejector.

I claim as my invention:

1. An automatic mixing and discharging system for plural liquids comprising the combination with containers for said liquids, of a siphon rising from one of the containers and descending through the other of them and having its discharge leg primed with the liquid of the said other container; and an ejector in said other container, arranged for flow from said other container into the discharge of the system, in which ejector the said flow is arranged to draw through the siphon.

'2. An automatic mixing and discharging system for plural liquids comprising, in combination, containers for the said liquids, a siphon from one of them' discharging into a tube which surrounds its discharge end; and said tube, having inlet from the other of said containers, whereby the liquid of said other container primes the discharge leg of the siphon, and adapted for the flow from the said tube todraw from the siphon; the joint discharge from said tube being a 10 mixture of the said liquids.

Signed at Providence, Rhode Island, this 25th day of July, 1924.

I I IRA V. KNIGHT. 

